An important step in the fabrication of a liquid crystal display device is filling the display cell with liquid crystal material. Typically, the display cell is in the form of two closely spaced parallel plates sealed around a substantial portion of their periphery. The cell is typically filled with liquid crystal material by dipping an edge of the plates containing an unsealed region into a trough of liquid crystal material (see FIG. 1). The liquid crystal material is drawn through the unsealed region by capillary force.
The disadvantages of this conventional process arise because liquid crystal material is expensive and easily contaminated. Since a substantial length of the LCD cell is immersed in the liquid crystal material, there is substantial opportunity for contamination of the liquid crystal material and, indeed, it is common practice to discard the remaining material in the trough after filling. The amount of liquid crystal material lost in this process typically exceeds the mount that is actually used in the cell. This loss of expensive material is wasteful and adds significantly to the cost of making an LCD display. Accordingly, there is a need for an improved apparatus and method for filling LCD cells.